ES2772831T3 - Variable speed generator-motor device and variable speed generator-motor system - Google Patents

Abstract

A variable speed generator-motor system comprising a power converter connected to a DC power source (901), comprising a positive pole (P) and a negative pole (N), and a three-phase synchronous machine (102B) which has damping coils and connected to one AC side through three terminals (R, S, T), in which all three terminals (R, S, T) are connected to neutral points (Ux, Vx, Wx) of three sets of three-terminal reactors (1003) and are configured to connect to a three-phase transformer (1002), first terminals (Up, Vp, Wp) of the three-terminal reactors (1003) are connected to terminals (a) on the side of the two-terminal three-arm machine (104RP, 104SP, 104TP) on the positive pole side of a modular multilevel converter, MMC, which are made up of k series-connected two-terminal unit converters (103) that are configured to emit an arbitrary voltage through an element energy storage device (203) that has the characteristic of a voltage source, where k is a natural number equal to one or greater, and terminals (b) of the positive pole of the arms are connected in a star to the positive pole (P) of the DC power supply (901), a few second terminals (Um, Vm, Wm) of the three-terminal reactors (1003) are connected to terminals (b) on the side of the two-terminal three-arm machine (104RN, 104SN, 104TN) on the negative pole side of the modular multilevel converter, MMC, which are made up of series connected unit converters (103), and terminals (a) on the negative pole side of the arms are star connected to the pole negative (N) of the DC power supply (901), the variable speed generator-motor system further includes: a first controller (905) configured to adjust a frequency and an amplitude of current supplied from the power converter to the synchronous machine (102B) to a fixed value; a second controller (905) configured to synchronize a frequency of current supplied from the power converter to the synchronous machine (102B) with a rotation speed of the synchronous machine (102B) and to adjust an amplitude of the current to a proportional value to the frequency; the variable speed generator-motor system being configured to use the first controller (905) or the second controller (905); and a switch (912, 914) configured to short circuit a field winding (908) of the synchronous machine (102B) with a resistor (913) when the first controller (905) is used and to connect the field winding (908) from the synchronous machine (102B) to an exciter (911) when the second controller (905) is used, and the variable speed generator-motor system is configured to use the first controller (905) when the synchronous machine (102B) is switched on. starts from rest, and to switch the control to be performed by the second controller (905) once the frequency reaches a set value, and in which the variable speed generator-motor system is also configured to temporarily stop the power converter MMC when the frequency reaches the set value, to allow the connection of the exciter (911) through the switch (912, 914).

Description

DESCRIPTION

Variable speed generator-motor device and variable speed generator-motor system

Countryside

The present invention relates to a variable speed generator-motor apparatus in which a modular multi-level PWM power converter (hereinafter referred to as "MMC converter" in the present invention) is connected to a rotating AC electric machine and a system variable speed generator-motor including the variable speed generator-motor apparatus.

Background

An MMC converter circuit is made up of unit converters that generate a desired voltage by controlling the modulation factor of a PWM converter that uses an energy storage element with the characteristics of a voltage source, such as a capacitor or a storage battery, as a source of tension. The voltage of the energy storage element for the drive converter fluctuates according to the charge and discharge performed with a period determined by the AC frequency. The unit's converters are connected in series to form a two-terminal arm. The first terminals of the two-terminal arms are connected to the terminals for the respective phases of an AC power source and the second star-connected terminals are connected to the terminal of a DC power source.

With this configuration, the arm connected to each phase generates a voltage with a desired AC frequency to control the alternating current and at the same time superimposes the direct current to perform the energy conversion with the DC power supply.

The control associated with the MMC converter includes current control to adjust an ARM current in accordance with an AC command and a DC command from an external source (such control will be referred to as "converter current control" in the following). present invention); a function of keeping the average voltage of the energy storage element in equilibrium between the unit converters by mutual adjustment of the modulation factors of the PWM converters provided in the unit converters within the arms (hereinafter referred to as said function will be referred to as "inter-stage control" in the present invention); and a function of keeping the total amount of energy stored in the energy storage element in the arm in balance between the arms (hereinafter, said function will be referred to as "interface balance control" in the present invention). The implementation of phase balance control requires a circuit element to reduce the current flowing between the arms.

Patent literature 1 discloses a technology in which a circulating current control reactor is provided between the first terminal of the arm for each phase and the terminal of the AC power supply (this will be referred to as a "DSMMC converter" in the present invention).

Patent literature 2 discloses a method in which a transformer including star connected double secondary and tertiary windings is provided to cancel the DC magnetomotive force generated in the transformer core due to circulating current while using the reactance of leakage of the secondary and tertiary windings as a current control circuit element (hereinafter referred to as "DIMMC converter" in the present invention).

Patent literature 3 discloses a method in which a transformer including secondary and tertiary windings connected in a zigzag is provided to cancel the DC magnetomotive force generated in the transformer core due to circulating current while using the leakage reactance of the secondary and tertiary windings as a current control circuit element (hereinafter referred to as "ZCMMC converter" in the present invention).

Non-patent literature 1 discloses a procedure for connecting the DC terminals of two DSMMC converters consecutively as a procedure for connecting the DC terminals of two MMC converters consecutively to be a variable frequency power supply, thus such as connecting one AC terminal to an AC system and connecting the other AC terminal to an AC rotating electrical machine to form a variable speed generator motor apparatus.

With this procedure, the direct current does not overlap in the rotating AC electrical machine connected to the MMC converter. Therefore, this method is suitable for varying the speed of the rotary electric machine AC is directly connected to the system C and operating at a fixed frequency.

Patent literature 4 discloses a procedure for connecting the ZCMMC converter to the side of the rotating AC electric machine. It is argued that, with such a procedure, an AC electrical system can be implemented without including the circulating current control reactor.

Patent literature 5 discloses a method for measuring variable frequency voltage / current signal vectors of rotating AC electrical machine.

Patent literature 6 discloses a mechanical and electrical energy conversion system comprising a three-phase electrical machine with a neutral wire, a MMC multi-level modular converter to generate arbitrary voltages, and an inductor with a zigzag winding and terminals for three phases and neutral. .

Appointment list

Patent Literature

Patent Literature 1: Japanese Patent No. 5189105

Patent Literature 2: International Publication WO 2009/135523

Patent Literature 3: Japanese Patent No. 5268739

Patent Literature 4: Japanese Patent Publication Open to Public No. 2013-162735

Patent Literature 5: Japanese Patent No. 5537095

Patent Literature 6: US Patent No. US2015008859

Non-Patent Literature

Non-Patent Literature 1: Makoto Hagiwara, Kazutoshi Nishimura and Hirofumi Akagi, “A Medium-Voltage Motor Drive with a Modular Multilevel PWM Inverter: Part I. Experimental Verification by a 400-V, 15-kW Downscaled Model Voltage with a Modular Multilevel PWM Inverter: Part I. Experimental Verification Using a Reduced Model of 400 V and 15 kW ”, The Transactions of the Institute of Electrical Engineers of Japan. D, 130 (4), pages 544-551, April 2010

Non-Patent Literature 2: Philip L. Alger, "Induction Machines", Second Edition, April 1969

Summary

Technical problem

Static power converters using power semiconductor switching devices (hereinafter referred to as "switching devices" in the present invention) can be roughly classified as an online switched current source converter (hereinafter referred to as "LCC converter "in the present invention) using a switching device without a self-extinguishing function, such as a thyristor, and a self-switching voltage source converter (hereinafter referred to as" VSC converter "in the present invention) using a switching device. switching with a self-extinguishing function, such as an IGBT.

With the VSC converter in particular, the temporal change rate of the coil voltage of a rotating electrical machine increases as the switching device voltage increases and as the switching characteristics improve, the PWM frequency increases. to suppress harmonic current, which causes an increase in coil leakage current.

This is a bottleneck, particularly in a case where the speed varies from the rotating AC electric machine that is installed under the assumption that there is a commercial AC frequency power supply. An MMC converter is classified as a VSC converter equipped with PWM control. Unlike a conventional PWM converter, the MMC converter includes N stages of unit converters connected in series to be able to suppress the width of the voltage pulsation due to PWM control at 1 / N without using a complex connection in the wiring of a reactor and a transformer and suppress the harmonic component of the voltage applied to the rotating AC electrical machine. The adoption of the ^m M ^c converter allows the use of the rotating electrical machine without reinforcing the insulation of the coil thereof and is particularly suitable for varying the speed of the rotating AC electrical machine that is installed under the assumption of a constant frequency of an AC power supply system.

Additionally, an MMC converter allows the number of serially connected drive converters to have redundancy so that availability can be increased by shorting the output terminal of a failed drive converter. Therefore, the MMC converter is suitable for varying the speed of a high capacity AC rotary electric machine that requires a large number of unit converters.

Non-patent literature 1 describes a suitable technology to realize such features. In patent literature 4 it is argued that the variable speed generator-motor apparatus can be implemented by connecting the ZCMMc converter.

However, the two publications mentioned above do not disclose any problems and solutions to the problems that inevitably arise when the speed of the rotating AC electric machine is varied using the MMC converter.

A first problem comes from the characteristic that the output current capacity of the MMC converter is proportional to the frequency. The current capacity decreases in a low-frequency output region, thus causing a problem because the starting torque of the AC rotating electric machine cannot be guaranteed because, in principle, the output torque of the machine is proportional to the current . There is a problem that such a converter cannot be applied to the starting of synchronous machines that make up the majority of high-capacity rotary electrical machines that are particularly suitable for using the characteristics of the MMC converter. This problem is common to all DSMMC, DIMMC and ZCMMC converters connected to the rotating AC electrical machine; however, problems and solutions thereof are not described in non-patent literature 1 and patent literature 4.

A second problem comes from the intentional superposition of direct current in a rotating electrical machine winding.

Non-patent literature 2 notes on page 356 that "even the imbalance in magnetic attraction due to a zigzag leakage flux caused by a combination of a stator and the number of center grooves of an induction machine rotor is makes it a problem. "

Also, when direct current is intentionally overlapping as with the DIMMC converter and the ZCMMC converter, the minimum requirement is the cancellation of the DC magnetomotive force generated by the coil current within the core slot. This problem is common in cases where synchronous machine and induction machine are adopted as the AC rotary electric machine.

On the other hand, it is argued in patent literature 4 that "when three-sectioned direct current is fed to each of the three-phase windings, the magnetic field generated by a zero phase current becomes zero."

Non-patent literature 2 presents three types of armature windings from page 76 to page 79. The same literature introduces a winding formed from a single layer coil in figure 3.5, a winding with a phase zone A 60-degree winding formed from a double-layer coil in Figure 3.6, and a 120-degree phase zone winding formed from a double-layer coil in Figure 3.7. Among these, the argument in patent literature 4 is valid only in the 120 degree phase zone configuration formed from the double-layer coil illustrated in Figure 3.7, where the argument states that "when the three-sectioned direct current fed to each of the three-phase windings, the magnetomotive force within a slot is canceled to cause the magnetic field generated by the zero phase current to be zero. " Now the three types of windings will be described.

As for the single layer coil, the coil current inside the slot is single phase; therefore, the magnetomotive force cannot be canceled in principle.

Figure 21 illustrates an example of a 60 degree phase zone formed from a double layer coil with the armature winding of a two pole motor housed in 18 slots.

Figure 21 illustrates a magnetomotive force distribution and a magnetic field distribution when the three-sectioned direct current is fed to each phase of the three-phase star-connected windings in figure 3.6 obtained by developing figure 3.3 in non-patent literature 2 on the circumference of a circle. It should be noted that in Figure 21, a solid line indicates an upper coil of the double layer coil and a broken line indicates a lower coil of the same.

Here, the diagram illustrates the distribution of the magnetomotive force generated by the winding of each phase when a three-sectioned direct current ICC / 3 is fed from terminal N to each of the three-phase terminals (RST), and the distribution of magnetomotive force y the distribution of the magnetic field due to the three summed phases. As illustrated in Figure 21, direct current generates a quasi-sinusoidal wave magnetic field flux distribution and is therefore not practical.

Next, Figure 7 illustrates an example of a 120 degree phase zone formed from the double layer coil with the armature winding of the two pole motor housed in 18 slots.

Figure 7 illustrates a magnetomotive force distribution and a magnetic field distribution when the three-sectioned direct current is fed to each phase of the star connected three-phase windings in Figure 3.7 of non-patent literature 2 when changing the winding of a winding short pitch (with 8/9 coil pitch) to full pitch winding. It should be noted that in Figure 7, a solid line indicates an upper coil of the double layer coil and a broken line indicates a lower coil of the same.

Here, the diagram illustrates the distribution of the magnetomotive force generated by the winding of each phase when the three-sectioned direct current ICC / 3 is fed from terminal N to each of the three-phase terminals (RST), and the distribution of magnetomotive force y the distribution of the magnetic field due to the three phases added. As illustrated in Figure 7, the magnetomotive force generated by the superposition of the direct current cancels out within each slot and does not contribute to the magnetic field distribution. Therefore, when the ZCMMC converter and the AC rotating electrical machine are connected to form the variable speed generator motor apparatus, it is necessary to "superimpose the trisected direct current in each phase of the armature winding in the phase zone of 120 degrees. formed from the "double layer coil" of the AC rotary electric machine.

However, when the speed of an existing AC rotating electrical machine is to be varied, in many cases the winding factor and the harmonic component are given priority and there are not necessarily a number of cases where the phase zone applies. 120 degrees. Consequently, the procedure in patent literature 4 can be applied to vary the speed of an existing machine in only a limited number of cases.

On the other hand, as for the armature winding with the 60 degree phase zone formed from the double layer coil, the procedure illustrated in Figure 4 can cancel the magnetomotive force generated by the superposition of the trisected direct current within of each slot so that the magnetomotive force does not contribute to the distribution of the magnetic field.

In figure 4, the three-phase terminal of figure 21 is divided for each of the magnetic poles generated by the three-phase coils, and then the direct current that will be superimposed on each of the first set of three-phase terminals (RP, SP, TP ) and the second set of three phase terminals (RN, SN, TN) are divided into three equal parts to superimpose the reverse direct current in polarity to each other.

Figure 4 illustrates the distribution of the magnetomotive force generated at this time by the winding of each phase, and the distribution of the magnetomotive force and the distribution of the magnetic field due to the three phases added. As illustrated in Figure 4, the magnetomotive force generated by the superposition of the direct current cancels within each slot so that it cannot contribute to the distribution of the magnetic field. However, there is a problem with the ZCMMC converter because direct current with opposite polarity cannot overlap.

An object of the present invention is to solve the aforementioned problems and to provide a variable speed generator-motor apparatus using a large AC generator motor and to provide a variable speed generator-motor system.

Solution to the problem

This object is solved with the characteristics of claim 1 of the device. Dependent claim 2 cites an advantageous embodiment of the invention.

Advantageous effects of the invention

According to the present invention, the AC rotating electric machine can be varied in speed simply by making a change in the coil ends of the armature winding of the AC rotating electric machine which is installed assuming that it is operated at a fixed frequency by an AC system. In particular, it is possible to rapidly vary the speed of rotating AC electrical machines in hydraulic power plants and pumped storage plants that are effective in suppressing the fluctuations of power systems that accompany the growth in the use of generated renewable energy. by solar power generation systems, wind power generation systems and the like.

Brief description of the drawings

Figure 1 is a circuit diagram illustrating a first embodiment of the present invention.

Fig. 2 is a circuit diagram of a unit converter in accordance with an embodiment of the present invention.

Figure 3 is a circuit diagram of another unit converter in accordance with one embodiment of the present invention.

Fig. 4 is a diagram illustrating an armature winding of an AC rotating electrical machine according to the first embodiment of the present invention.

Figure 5 is a control block diagram illustrating the first embodiment of the present invention.

Figure 6 is a circuit diagram illustrating a second embodiment of the present invention. Fig. 7 is a diagram illustrating an armature winding of an AC rotating electrical machine according to the second embodiment of the present invention.

Figure 8 is a control block diagram illustrating the second embodiment of the present invention.

Figure 9 is a circuit diagram illustrating a third embodiment of the present invention.

Figure 10 is a circuit diagram of a DC power supply according to the third embodiment of the present invention.

Fig. 11 is a circuit diagram of another DC power supply in accordance with the third embodiment of the present invention.

Fig. 12 is a diagram illustrating an armature winding of an AC rotary electrical machine in accordance with the third embodiment of the present invention.

Figure 13 is a control block diagram illustrating the third embodiment of the present invention.

FIG. 14 is an operation sequence diagram illustrating the third embodiment of the present invention.

Figure 15 is a circuit diagram illustrating a fourth embodiment of the present invention. Figure 16 is a circuit diagram of a DC power supply according to the fourth embodiment of the present invention.

FIG. 17 is a diagram illustrating an armature winding of an AC rotating electrical machine in accordance with the fourth embodiment of the present invention.

Figure 18 is a control block diagram illustrating the fourth embodiment of the present invention.

Figure 19 is a control block diagram illustrating a fifth embodiment of the present invention.

Figure 20 is an operation sequence diagram illustrating the fifth embodiment of the present invention.

Fig. 21 is a diagram illustrating an armature winding of a conventional AC rotating electrical machine (a single star connected 60 degree phase zone).

Fig. 22 is a diagram illustrating an armature winding of a conventional AC rotating electrical machine (a star connected 60 degree double phase zone).

Fig. 23 is a diagram illustrating an armature winding of a conventional AC rotating electrical machine (a star connected 120 degree double phase zone).

Description of modes of implementation

Embodiments of a variable speed generator-motor apparatus and a variable speed generator-motor system according to the present invention will now be described in detail with reference to the drawings. It should be noted that the present invention is not limited by the embodiments.

(First mode of realization)

Figure 1 is a circuit diagram illustrating a first embodiment of the present invention.

There is a 101A DC power supply and a 102A AC rotary electric machine. The AC 102A rotary electric machine includes two sets of star connections and is provided with three-phase terminals (RP, SP, TP) and three-phase terminals (RN, SN, TN), where the neutral points of the two sets of star connections they are bonded together so that they extend to terminal N and are connected to ground through a high resistance. There are six arms (104RP, 104SP, 104TP, 104RN, 104SN, 104TN), each of which includes two terminals (a, b) and is made up of N series-connected output terminal stages (x, y) of converters of units 103 of an MMC converter, where the b terminals of the three arms (104RP, 104SP, 104TP) are star connected to the first terminal (P) of the DC power supply 101A and the arms terminals a are connected to the three phase terminals (RP, SP, TP) of the AC 102A rotating electrical machine. Terminals a of the remaining three arms (104RN, 104SN, 104TN) are star connected to the second terminal (N) of DC power supply 101A and terminals b of the arms are connected to three-phase terminals (RN, SN , TN) of the rotary electric machine of CA 102A.

A control device 105A receives a signal from each of the DC current transformers 106 that measures the output current of the six arms, a DC voltage transformer 107A that measures the line voltage across the three-phase terminals (RP, SP, TP), a voltage transformer CC 107B measures the line voltage across the three-phase terminals (RN, SN, TN) and a phase detector 108 that measures the rotational phase 0 expressed in electrical degrees, and then performs a control operation to output gate signals (GateP *, GateN *) to the converters of unit 103. Disconnectors 109A and 109B are closed during normal operation and open during maintenance. The phase detector 108 can also estimate the rotational phase 0 by performing a vector operation on the basis of the line voltages measured by the DC voltage transformer 107 and 107B and the current signals of the current transformers 106 CC.

Patent literature 5 discloses a method for performing a vector operation on an AC signal that changes with rotation speed / frequency, as well as a method for calculating the phase of the internal induced voltage corresponding to the rotation phase 0 on the basis to a voltage signal and a current signal. Fig. 2 is a circuit diagram of the unit converter 103 according to the first embodiment. The unit converter 103 is configured such that a switching device 201 and a switching device 202 that form a bidirectional switch circuit are connected to a capacitor 203, which functions as an energy storage element having source characteristics. tensile. Drive converter 103 performs PWM control with an input gate signal, from a fiber optic cable 204A connected to control device 105A, to a gate controller 207A for switching devices 201 and 202 through an element photoelectric conversion converter 205A and a series-parallel conversion circuit 206A and then adjusts the average voltage across the two terminals (x, y) between zero and a capacitor voltage VC. On the other hand, the capacitor voltage VC feeds an analog signal emitted by a DC voltage transformer 208 to the control device 105A through the fiber optic cable 204A through an analog-digital converter 209, a series-parallel converter 210 and an electro-optical conversion element 211. With this configuration, current flows through any of the switching devices 201 and 202; therefore, the loss can be minimized.

Fig. 3 is a circuit diagram of another form of the unit converter 103 according to the first embodiment. A unit converter 103B includes switching devices 212, 213, 214 and 215 that form a complete bridge circuit instead of the bi-directional switch circuit illustrated in Figure 2. With this configuration, with the capacitor voltage as VC, the average voltage at the (x, y) terminals you can set between -VC and VC.

Fig. 4 illustrates an example of an armature winding of the AC rotating electrical machine and the terminal connection according to the first embodiment. For the sake of simplicity, the figure illustrates an example of a two-pole 18-slot motor, which is close to a minimum configuration. Furthermore, a high-pole synchronous machine illustrated here to facilitate understanding of a relationship with a field system may be a cylindrical synchronous machine or an induction machine.

It is described below that the winding and terminal configuration in Figure 4 can be implemented by changing the coil end connections and removing terminals based on the winding configuration and terminals illustrated in Figure 21.

Figures 21 and 4 have a 60 degree phase zone configuration formed by a double layer coil and there is no change in the portions of the coil that pass through the slots. In figure 21, which illustrates the configuration before the alteration, you have a normal single star connection of three-phase terminals (R, S, T), where the coils generating a magnetic field of positive / reverse polarity in a space are connected serially. In figure 4, which illustrates the configuration after alteration, you have two sets of three-phase terminals (RP, SP, TP) and (Rn, SN, TN).

As described above, the alteration involves a change in the connections of the ends of the armature winding coil and a further removal of the three terminals. The change in the connections halves the number of turns of the three-phase windings, so that the line voltage is equal to half the value before the alteration. The current capacity of the armature coil does not change due to alteration. However, the way the current capacity is used changes due to disturbance.

The following describes a case where a synchronous machine is used as a rotating AC electric machine. The frequency of the current before the disturbance corresponds to the frequency of the AC system, where the effective value of the current is equal to the square of the sum of the roots of the active power component and the reactive power component. The current after alteration is equal to the square of the sum of the roots of the effective value of the output frequency component of a power converter and the average value of the direct current. In principle, the phase voltages of the two sets of three-phase terminals are in phase and have the same effective value. Where the signs of the alternating currents (IRP_AC, ISP_AC, ITP_AC) and (IRN_AC, ISN_AC, ITN_AC) flowing through two sets of windings are defined in figure 1, the currents are in opposite phases and have equal effective value . The power factor of alternating current is controlled so that it becomes unity. Here, VAC is assumed to indicate the AC phase voltage of the power converter, ICA indicates the effective value of the current, and ICC denotes the direct current that is tripled for the windings of the respective phases. With VCC indicating the output voltage of the DC power supply 101A, the relationship with an output capacity P becomes (P = 6 * VAC * ICA = VCC * ICC), at which the loss of the machine rotary AC electric and power converter is ignored. The ratio of (ICC / 3) to ICA varies depending on the capacities of the capacitors 203 of the unit converters 103 and the operating procedure at the time of the power failure and also which of the unit converters in figures 2 and 3 is used.

In general, the ratio of (ICC / 3) increases and an equivalent power factor decreases when the capacitor 203 capacity is reduced, the capacitor voltage utilization factor VC is reduced by reducing the upper and lower limits of the factor PWM modulation of the drive converter to increase availability (continuity of operation) at the time of power failure, and the bidirectional switch circuit in figure 2 is used as the drive converter with importance given to the efficiency of the converter power. When the ratio of (ICC / 3) is designed to be high, the ratio is approximately equal to (ICC / 3) / ICA = 0.5. As a result, the equivalent power factor is reduced to approximately 0.9 with ICA as the active component of the current capacity contributing to the output and superimposed DC (ICC / 3) as the reactive component. This value does not imply a schematic of the MMC converter.

As a result, when the nominal power factor of the synchronous machine before the disturbance is equal to 0.9 or less, the same active output power after the disturbance can be guaranteed. The power factor cannot be adjusted when using an induction machine such as AC rotary electric machine, in which case the active power output after alteration is reduced to a value multiplied by the equivalent power factor of the MMC converter. .

Figure 5 is a control block diagram of the control device 105A according to the first embodiment.

A phase voltage calculating unit 501A calculates the phase voltage signal from two sets of three-phase line voltage detection signals. A speed calculating unit 502 calculates a rotation speed frequency w based on the current value of rotation phase 0 and the number of samples Np of an in-phase signal in a previous period. Here, where At indicates a sampling period, there is a relationship w = 2 * n / (Np * At).

A moving average calculation unit 503A calculates the direct current ICC by finding the moving average of the sum of the three-phase alternating current (IRP, ISP, ITP) Np times. A d-q converter 504P performs a calculation according to expression 1, and a d-q converter 504N performs a calculation according to expression 2. It should be noted that the phase sequence is RST in this case.

[Expression 1]

eos 8 cos (8-27i / 3) eos

sin6 sin {9 - 2ti/3) sin

sin6 sin {9 - 2ti / 3) sin

. . . (expression 1)

[Expression 2]

IRN

cosO eos {8 - 27i / 3j eos (0 271/3)

ISN

sin0 sin (0 - 2^tc/ 3) sin (9 2s/3)

sin0 sin (0 - 2 ^tc / 3) sin (9 2s / 3)

fTN

■■ • (expression 2}

A power calculating unit 505A employs an instantaneous symmetric coordinate method to calculate the active power P and the reactive power Q from a rotational phase signal, a phase voltage signal, and an alternating current signal.

An active power setting unit 506A and a reactive power setting unit 507A issue current commands ID * and IQ *, so that the command values P * and Q * correspond to the calculated values P and Q, respectively . A 508A AC setting unit performs a control operation such that one of the command values obtained by bisecting the command value ID * corresponds to a measured / calculated value IDP and a command value obtained by reversing the polarity of another of the command values corresponds to a measured / calculated value IQP, and performs a control operation so that one of the command values obtained by dividing the command value IQ * corresponds to a measured / calculated value IQP and a value The command value obtained by inverting the polarity of another of the command values corresponds to a measured / calculated value IQN. A DC setting unit 509A performs a control operation such that a DC command ICC * obtained by dividing an output command value P * by an output voltage VCC * from a DC power supply corresponding to the value measured / calculated ICC.

In the present embodiment, the degree of freedom of a current path is five, where there are four integration calculators in the AC setting unit 508A and there is an integration calculator in the DC setting unit 509A. The total of five integration calculators corresponds to the five degrees of freedom of the current route. Therefore, all integrators can independently keep the input deviation at zero. Inverse d-q converters 510P and 510N perform a calculation according to expression 3.

[Expression 3]

A DC voltage command correction calculation unit 511P is provided for arms 104RP, 104SP and 104TP and a DC voltage command correction calculation unit 511N for arms 104RN, 104SN and 104TN, where the units of The calculation outputs the VRP *, VSP *, VTP *, VRN *, VSN * and VTN * output voltage commands corresponding to the arms.

Consequently, the three-phase terminals (RP, SP, TP) and the three-phase terminals (RN, SN, TN) of the rotating AC electric machine 102A have approximately equal phase voltages of (VR *, VS *, VT *); therefore, the output voltage commands for arms 104RP and 104RN are roughly given by VRP * = VR * (1/2) x VCC y

VRN * = -VR * (1/2) x VCC, respectively.

The PWM 512P and 512N computing units therefore issue gate commands GateP * and GateN * based on those output voltage commands and the capacitor voltage VC of unit converter 103. (Second embodiment)

Figure 6 is a circuit diagram illustrating a second embodiment of the present invention. There is a DC power supply 101A and a rotary AC machine 102B. The AC 102B rotary electrical machine includes a star connection assembly and is provided with three-phase terminals (R, S, T), where the neutral point of the star connection is drawn to terminal N to connect to the second terminal (N) from the DC power supply 101A. There are three arms (604R, 604S, 604T), each of which includes two terminals (a, b) and is made up of N series connected output terminal stages (x, y) of the 103 unit converters of a MMC converter, where the terminals a of the three arms are connected to the three-phase terminals (R, S, T) of the rotating AC electric machine 102B and the terminals b of the arms are star connected to the first terminal (P) of the DC power supply 101A.

A control device 605A receives a signal from each of the DC current transformers 106 that measures the output current of the three arms, a DC voltage transformer 607 that measures the line voltage across the three-phase terminals (R, S, T) and detector phase 108 which measures the rotational phase 0 expressed in electrical degrees, and then performs a control operation to output a gate signal Gate * to the converters of unit 103. A disconnector 609 is closed during the normal and open operation during maintenance. The phase detector 108 can also estimate the rotational phase 0 by performing a vector operation based on the line voltage measured by the DC voltage transformer 607 and a current signal from the DC current transformers 106. FIGS. 2 or 3 may be referred to as an embodiment of the unit converter 103.

Fig. 7 illustrates an example of an armature winding of the AC rotating electrical machine and the terminal connection according to the second embodiment. For the sake of simplicity, the figure illustrates an example of a two-pole 18-slot motor, which is close to a minimum configuration. Furthermore, a high-pole synchronous machine illustrated here to facilitate understanding of a relationship with a field system may be a cylindrical synchronous machine or an induction machine.

The winding illustrated in Figure 7 has a 120 degree phase zone configuration formed by a double layer coil. It is a normal single star connection with the three phase terminals (R, S, T) removed. The following describes a case where the AC rotating electric machine is a synchronous machine. The current before the disturbance corresponds to the frequency of the AC system, where the effective value of the current is equal to the square of the sum of the root of the active power component and the reactive power component. The current after alteration corresponds to the output frequency of a power and direct current converter. The power factor of alternating current (IR, IS, IT) is controlled so that it becomes unity. Here, it is assumed that VAC and ICA indicate the AC phase voltage and the effective value of the power converter current, respectively, and that ICC indicates the superimposed direct current that is tripled for the windings of the respective phases. With VCC indicating the output voltage of the DC power supply 101A, the relation to the output capacity P becomes (P = 3 * VAC * ICA = VCC * ICC), at which the loss of the machine rotary AC electric and power converter is ignored. The ratio of (ICC / 3) to ICA is similar to the case in Figure 1 and therefore will not be described to avoid repetition. When the nominal power factor of the synchronous machine before the disturbance is equal to 0.9 or less, the same active output power after the disturbance can be guaranteed. The power factor cannot be adjusted when using an induction machine such as the AC rotary electric machine, in which case the active power output after alteration is reduced to a value multiplied by the equivalent power factor of the converter ^m M ^c .

Figure 8 is a control block diagram of the control device 605A in accordance with the second embodiment.

A phase voltage calculating unit 501B calculates the phase voltage signal from the line voltage detection signal. The control device 605A also includes the speed calculating unit 502 and the moving average calculating unit 503A that calculates the DC ICC by finding the moving average of the sum of the three-phase alternating current (IR, IS, IT) Np times. A d-q converter 504C performs a calculation according to expression 4. It should be noted that the phase sequence is RST in this case.

[Expression 4]

GO

COS0 cos (G - 2 ^te / 3) cos (B 2 ^tí / 3)

1S

sinfc) sin {9 ~ 2re/3) sín(fl 2n/3)_

sinfc) sin {9 ~ 2re / 3) sin (fl 2n / 3) _

ITEM

•. ■ (expression 4}

A power calculating unit 505B employs the instantaneous symmetric coordinate method to calculate the active power P and the reactive power Q from a phase voltage signal and an alternating current signal.

An active power adjustment unit 506B and a reactive power adjustment unit 507B issue current commands ID * and IQ *, so that the command values P * and Q * correspond to the calculated values P and Q, respectively . An alternating current setting unit 508B performs a control operation so that the command values ID * and IQ * correspond to the measured / calculated values ID and IQ, respectively. A DC setting unit 509B performs a control operation such that a DC command ICC * obtained by dividing an output command value P * by an output voltage VCC * from a DC power supply corresponding to the value measured / calculated ICC.

In the present embodiment, the degree of freedom of a current path is three, where there are two integration calculators in the alternating current adjustment unit 508B and there is one integration calculator in the direct current adjustment unit. This means that there are three integration calculators in total. Therefore, all integration calculators can independently keep the input bias at zero. An inverse d-q converter 510C performs a calculation according to expression 3.

A DC voltage command correction calculation unit 511C is provided for the 604R, 604S and 604T arms, and the calculating unit issues the output voltage commands VR *, VS * and VT * corresponding to the arms.

Consequently, when the three-phase terminals (R, S, T) of the AC rotating electrical machine 102B have phase voltages of (VRG *, VSG * VTG *), the output voltage command for arm 104R is given by VR * = VRG * (1/2) x VDC.

A PWM computing unit 512C thus issues a gate command Gate * based on those output voltage commands and the capacitor voltage VC of drive converter 103.

(Third mode of realization)

Figure 9 is a circuit diagram illustrating a third embodiment of the present invention. Here, an AC rotating electric machine 902 is a synchronous machine including a damper winding. The AC 902A rotary electrical machine including two sets of star connections is provided with three-phase terminals (RP, SP, TP) and three-phase terminals (RN, SN, TN), where the neutral points of the two sets of star connections they are bonded together so that they extend to terminal N and are connected to ground through a high resistance.

A DC power supply 901 performs power conversion between the AC system side terminals (A, B, C) and the DC side terminals (P, N). The side terminals of the AC system (A, B, C) are connected to an AC system 903 through a switch 904.

The 901 DC power supply also includes three sets of AC terminals (UP, VP, WP), (UM, VM, WM) and (UX, VX, WX). The AC terminals (UP, VP, WP) are connected to the three-phase terminals (RP, SP, TP) of the 902A AC rotating electrical machine through a 905P disconnector and a 906 switch. The AC terminals (UM, VM, WM) are connected to the three-phase terminals (RN, SN, TN) of the AC rotating electrical machine 902A through a disconnector 905N. Furthermore, the three-phase terminals (RP, SP, TP) and the three-phase terminals (RN, SN, TN) are connected by disconnectors 907A and 907B. The AC terminals (UX, VX, WX) branch into a 920 home power supply system and a 911 field power converter through a 909 field breaker and a 910 field transformer. A 908 field winding it is interchangeably connected by a switch 914 connected to a resistor 913 and a switch 912 connected to the field power converter 911.

AC system 903 is connected to AC terminals (UP, VP, WP) and (UM, VM, WM) through a 915 initial load transformer, 916 initial load switch, 917 current limiting resistor and an initial load connection switch 918. A bypass breaker 919 is provided for the current limiting resistor 917.

FIG. 10 is a circuit diagram illustrating one embodiment of a DC power supply 901A using the DIMMC converter described in patent literature 2.

The primary windings of a 1001 transformer are connected to the side terminals of the AC system (A, B, C), and the secondary and tertiary windings are connected to the AC terminals (UP, VP, WP) and (UM, VM , WM) with double star connection. The AC terminals (Up, Vp, Wp) of transformer 1001 are connected to terminals a of three two-terminal arms (1004UP, 1004VP, 1004WP) each consisting of unit converters connected in series 103, and terminals b of the arms are star connected to the DC terminal (P). On the other hand, the AC terminals (Um, Vm, Wm) are connected to the terminals b of three arms of two terminals (1004UM, 1004VM, 1004WM) each formed by unit converters connected in series 103, and the terminals a of the arms are star connected to the DC terminal (N). The transformer 1001 is provided with delta-connected fourth windings that have the function of supplying the power supply of a house and a field circuit, as well as the function of suppressing a third harmonic.

FIG. 11 is a circuit diagram illustrating another embodiment of a DC power supply 901B using the DSMMC converter described in patent literature 1.

Reference numerals identical to those assigned in Figure 10 indicate identical components, which will not be described to avoid repetition.

The primary windings of a transformer 1002 are connected to the side terminals of the AC system (A, B, C), and the terminals (Ut, Vt, Wt) of the secondary windings connected to the delta are connected to the neutral points (Ux , Vx, Wx) of three sets of three-terminal reactors 1003. Terminals (Up, Vp, Wp) of three-terminal reactors 1003 are connected to terminals a of two-terminal three-arm (1004UP, 1004VP, 1004WP) , each consisting of series connected unit converters 103, and the b terminals of the arms are star connected to the DC terminal (P). On the other hand, the terminals (Um, Vm, Wm) of the three-terminal reactors 1003 are connected to the terminals b of three two-terminal arms (1004UM, 1004VM, 1004WM) each formed by unit converters connected in series 103 , and the terminals a of the arms are star connected to the DC terminal (N). The secondary windings of transformer 1002 feed a domestic power supply and a field circuit through AC terminals (UX, VX, WX).

The following describes a procedure to charge the capacitor 203 of the unit converter 103 of the DC power supply 901 with the configuration illustrated in Figure 9. The disconnectors 905P and 905N are kept open during the charging period.

When the initial load breaker 916 and the initial load connection breaker 918 are closed while the bypass circuit breaker 919 is held open, the capacitors 203 of the unit converters 103 begin to charge while the current limiting resistor 917 suppresses the input current. Bypass circuit breaker 919 then closes to speed up charging. Initial load connect switch 918 opens once charging is complete with diode rectification voltage across AC terminal of initial load transformer 915, followed by closing switch 904 to load transformer 10001 or 1002 from the DC power supply 901, and the unit converters 103 then perform PWM control to charge the capacitors 203 so that the capacitor voltage is driven to the desired voltage.

Next, the DC power supply 901 powers the unit converters 103 of each of the six arms (104RP, 104SP, 104TP, 104RN, 104SN, 104TN) on the side of the AC 902A rotary electric machine and, therefore, the capacitor 203 of each unit converter is charged by the PWM control. Once charging is completed in the aforementioned manner, only the unit converters 103 on the DC power supply side 901 can be driven with the AC rotary electric machine 902A stopping to operate as a power setting unit. reactive power. When a Francis pump turbine is connected directly to the AC 902A rotary electric machine, the directions of power generation and water pumping have reversed phase sequences, which however can be changed simply by controlling a converter, and thus , a phase reversal disconnect is not required.

According to the present embodiment, all converters of the unit are already charged and therefore can be quickly started for operations in the rotational directions of power generation and electrical operation.

Fig. 12 illustrates an example of an armature winding of the AC rotary electrical machine and the terminal connection according to the third embodiment. For simplicity, the figure illustrates an example of a 36-slot four-pole motor, which is close to a minimum configuration. Furthermore, a high-pole synchronous machine illustrated here to show a relationship with a field system may be a cylindrical field synchronous machine or an induction machine.

The winding and terminal configuration in Figure 12 can be implemented simply by making a change to the coil ends of the windings and the terminal configuration illustrated in Figure 22. Figure 22 illustrates a double star connected four pole motor With a 60 degree phase zone configuration composed of a general double layer coil. The figure illustrates an example of three windings on the positive pole side and three windings on the negative pole side, giving a total of six windings in each phase. The star connection has a double parallel by an interpolar crossing.

On the other hand, the winding of a set of three-phase terminals (RP, SP, TP) in Figure 12 has two positive poles connected in series to provide a total of six windings. The winding of the other set of three-phase terminals (RN, SN, TN) has two negative poles connected in series to provide a total of six windings.

According to the embodiment in figure 12, the number of windings does not change before and after the alteration; therefore, the rated voltage can be maintained. Consequently, a device such as switch 906 can be used. When the embodiment illustrated in Fig. 11 is adopted as the DC power supply, the terminal voltage on the secondary side of transformer 1002 does not change before and after the alteration; therefore, transformer 1002 can be used.

The configuration illustrated in figure 9 allows operation without going through the MMC converter. Specifically, the 905P and 905N disconnectors, the 906 switch, and the 907A and 907B disconnectors are closed to allow the 902A AC rotating electrical machine to operate as a three-phase, double-star generator. When a Francis pump turbine is to be connected directly to the machine, the connection can be made in such a way that the phase sequence follows the power generation direction and therefore the machine can perform a generating operation. of power without going through the MMC converter.

Figure 13 is a control block diagram of a control device 905 in accordance with the third embodiment. Reference numerals identical to those assigned in Figure 5 indicate identical components, which will not be described to avoid repetition.

A command switch (SW1) 1301 toggles a command between a fixed start frequency wS and a rotational speed frequency w. A current command generator 1302 outputs a current command ID * proportional to the rotational speed frequency w. A current command generator 1303 outputs ID * = 0. A command switch (SW2) 1304 selectively performs the switch between the active power setting unit 506A, the current command generator 1302 and the current command generator 1303 to issue the stream command ID *.

A command switch (SW3) 1305 selectively performs the switching between an active power command P * and an active power measurement P. A power calculation unit 1306 is configured in such a way that the output of an effective voltage value of VGM line of AC generator-motor 902A is added to power calculating unit 505. A voltage command generator 1307 generates a voltage command VGM * proportional to the frequency of rotation speed w, an adjustment unit is provided of voltage 1308 for the AC motor generator 902A, and a current command generator 1309 outputs IQ * = 0. A command switch (SW4) 1310 selectively performs the switching between the voltage adjustment unit 1308, the generator of current command 1309 and reactive power setting unit 507A to issue current command IQ *.

Figure 14 illustrates a procedure for starting the alternating current generator-motor apparatus in the aforementioned embodiment illustrated in Figures 9 and 13.

First, a procedure for starting the machine in engine mode will be described.

At time Tm1 in FIG. 14, the capacitors of the unit converters 103 are already charged in advance, the switch 904 is closed, and the disconnectors 905P, 905N, 907A, and 907B are kept open.

A CBE2 switch is closed (ON), a CBE3 switch is open (OFF), the command switch SW1 is set on the fixed side of the constant speed command wS, and the command switch SW2 is on the side of an ID command * (ID * = kw) proportional to speed. The command switch SW3 is set to the active power measurement side P, and the command switch SW4 is set to IQ * = 0.

When the MMC converter is started at the time Tm2 in the above-mentioned state (MMC control_ON), the AC rotating electric machine 902A is started in an induction machine mode by a damping winding. The MMC converter stops temporarily (MMC control_OFF) when the rotation speed reaches a value equivalent to the set value wS at time Tm3, at which point the CBE3 closes to connect to the field power converter 911. Then, at the moment Tm4, CBE2 opens to disconnect resistor 913. At the same time, the command switch SW1 is switched to the side of the frequency of rotation speed w (rotation speed w) and the command switch SW4 is switched to output side (AVR) of the voltage adjusting unit 1308. This causes each of the ID * and IQ * commands to generate a command value proportional to speed. At the same time, field control starts. When the control of the MMC converter (MMC control_ON) is started at time Tm5 while maintaining the state mentioned above, the machine starts to accelerate with the synchronous torque of the machine. Once the rotation speed w enters a variable speed operating range, the output of the command switch SW2 is switched to ID * = 0 temporarily at time Tm6, then at time Tm7, the command switch SW2 is switched set to the output side (APR) of the active power setting unit, the command switch SW3 is set to the command side P *, and the command switch SW4 is set to the output side (AQR) of reactive power adjusting unit, causing the machine to enter operation in a normal variable speed motor mode.

According to the present embodiment described above, the machine can perform an automatic start in engine mode without depending on a starting device.

Next, a procedure for starting the machine in generator mode will be described.

At Tg1 in FIG. 14, the capacitors 203 of the unit converters 103 are already charged in advance, the switch 904 is closed, and the disconnectors 905P, 905N, 907A and 907B are kept open. The CBE2 switch is open, the CBE3 switch is closed, the SW1 command switch is not used (set to one side as the output is not determined), and the SW2 command switch is on the side of ID * = 0. The Command switch SW3 is set to the active power measurement P side, and command switch SW4 is set to the output side of the voltage setting unit.

In generator mode, the rotational speed is controlled by a speed regulator of a motor connected directly to the AC 902A rotary electric machine, so that the machine is started and accelerated with a torque on the motor side.

In the state mentioned above, in Tg1, the machine accelerates while the speed regulator on the motor side adjusts the speed. The AC 902A rotary electric machine remains unloaded. After the rotational speed reaches a variable speed range, a rotational speed command for the speed regulator remains constant at Tg2. At this time, a phase 0 signal corresponds to a rotational phase; therefore, the voltage phase induced at the terminal of the AC rotating electrical machine 902A and the voltage command phase are in phase with each other. In Tg3, the MMC control starts while at the same time the command switch SW4 is switched to the reactive power setting unit side. Then in Tg4, the command switch SW2 is switched to the output side of the active power setting unit, and the command switch SW3 is switched to the side of the active power command P *, which causes the machine to input to operation in a normal state variable speed generator mode. (Fourth mode of realization)

Figure 15 is a circuit diagram illustrating a fourth embodiment of the present invention. Reference numbers identical to those assigned in Figures 6 and 9 indicate identical components. These components will not be described to avoid repetition. Here, an AC 1502A rotating electric machine is a synchronous machine that includes a damper winding.

AC 1502A rotary electric machine including two sets of star connections is provided with three-phase terminals (R1, S1, T1) and three-phase terminals (R2, S2, T2), where the neutral points of the two sets of stars the connections are linked together so that they extend to the N terminal and connect to the second (N) terminal of a 1501 c power supply. There are six arms (1504R1, 1504S1, 1504T1, 1504R2, 1504S2, 1504T2), each of which includes two terminals (a, b) and is formed by N stages of output terminals connected in series (x, y) of the unit converters 103 of an MMC converter, where the b terminals of the three arms (1504R1, 1504S1, 1504T1) are connected in star to the first terminal (P) of the DC power supply 1501 and the terminals a of the arms are connected to the three phase terminals (R1, S1, T1) of the rotating electrical machine of CA 1502A. Terminals a of the remaining three arms (1504R2, 1504S2, 1504T2) are star connected to the first terminal (P) of DC power supply 1501 and terminals a of the arms are connected to three-phase terminals (R2, S2 , T2) of the AC 1502A rotary electric machine.

A control device 1605 receives a signal from each of the six current transformers CC 106, a voltage transformer CC 107C that measures the line voltage across the three-phase terminals (R1, S1, T1), a voltage transformer CC 107D that measures the line voltage of the three-phase terminals (R2, S2, T2) and the phase detector 108 that measures the rotational phase 0 expressed in electrical degrees, and then performs a control operation to output gate signals (Gate1 * , Gate2 *) to the converters of unit 103. A disconnector 1505 is closed during normal operation and open during maintenance. A disconnector 1507 is open during normal operation and closed during bypass operation.

DC power supply 1501 performs power conversion between the AC system side terminals (A, B, C) and the DC side terminals (P, N). The side terminals of the AC system (A, B, C) are connected to the AC system 903 through the switch 904.

The 1501 DC power supply also includes two sets of AC terminals (U, V, W) and (UX, VX, WX). The AC terminals (U, V, W) branch on switch 1507 through switch 1505 and a switch 1506 and then connect to the two sets of 3-phase terminals (R1, S1, T1) and (R2, S2, T2) of the alternating current rotating electric machine. The AC terminals (UX, VX, WX) branch into the 920 home power supply system and the 911 field power converter through the 909 field breaker and the 910 field transformer. The 908 field winding is Switchable connected by switch 914 connected to resistor 913 and switch 912 connected to field power converter 911.

The AC system 903 is connected to the AC terminals (U, V, W) through the initial load transformer 915, the initial load switch 916, the current limiting resistor 917 and an initial load connection switch 1518 Bypass breaker 919 is provided for current limiting resistor 917. Figure 16 is a circuit diagram illustrating one embodiment of DC power supply 1501 using the ZCMMC converter described in patent literature 3 .

The primary windings of a 1601 transformer are connected to the side terminals of the AC system (A, B, C), and the secondary and tertiary windings are connected in a zigzag to connect to the AC terminals (U, V, W). The AC terminals (U, V, W) of transformer 1601 are connected to terminals a of three two-terminal arms (1602U, 1602V, 1602W) each consisting of series connected unit converters 103, and terminals b of the arms are star connected to the DC terminal (P). On the other hand, the neutral point of the zigzag connection is connected to the DC terminal (N). The transformer 1601 is provided with a delta-connected winding that has the function of supplying the power supply of a house and a field circuit, as well as the function of suppressing a third harmonic. Fig. 17 illustrates an example of an armature winding of the AC rotating electrical machine and the terminal connection according to the fourth embodiment. For simplicity, the figure illustrates an example of a 36-slot four-pole motor, which is close to a minimum configuration. Furthermore, a high-pole synchronous machine illustrated here to show a relationship with a field system may be a cylindrical field synchronous machine or an induction machine.

The winding and terminal configuration in Figure 17 can be implemented by simply making a change to the coil ends of the windings and the terminal configuration illustrated in Figure 23. Figure 23 illustrates a double star connected four pole motor With a 120 degree phase zone configuration composed of a general double layer coil. The example illustrated in the figure has six windings for each phase. The star connection has a double parallel by an interpolar crossing.

On the other hand, in figure 17, the double star connection is divided into two sets to extract independent terminals, where the number of windings of each of the first set of three-phase terminals (R1, S1, T1) and the second set of Three phase terminals (R2, S2, T2) is six in total as with figure 23.

According to the embodiment in Figure 17, the number of windings does not change before and after the alteration; therefore, the rated voltage can be maintained. Consequently, a device such as switch 1506 can be used.

The configuration illustrated in figure 15 allows operation without going through the MMC converter. Specifically, disconnector 1505, switch 1506, and disconnector 1507 are closed to allow rotating AC electrical machine 1502A to operate as a three-phase, double-star generator. When a Francis pump turbine is to be connected directly to the machine, the connection can be made in such a way that the phase sequence follows the power generation direction and therefore the machine can perform a generating operation. of energy without going through the converter m Mc.

According to the embodiment in Fig. 17, when the star connection is in parallel while increasing the current capacity of the AC 1502A rotating electrical machine, the current flowing through each arm can be reduced by dividing the parallel winding in equal parts and pulling out the split terminals. This makes it possible to reduce the number of parallel connections of the switching devices in the unit converter 103; therefore, the configuration can be simplified and the reliability can be improved. Figure 18 is a control block diagram of the control device 1605 according to the fourth embodiment. Reference numbers identical to those assigned in Figures 5 and 8 indicate identical components, which will not be described to avoid repetition.

A phase voltage calculating unit 1801A calculates the phase voltage signal from a line voltage sense signal. The 1605 control device also includes the speed calculating unit 502 and the moving average calculating units 503A and 503B that calculate the direct currents ICC1 and ICC2 by finding the moving average of the sum of the two sets of three-phase alternating current ( IR1, IS1, IT1) and (IR2, IS2, IT2) Np times. The D-q converters 1804A and 1804B perform a calculation according to expression 4 to the output (ID1, IQ1) and (ID2, IQ2), respectively. It should be noted that the phase sequence is RST in this case.

A power calculating unit 1806 employs an instantaneous symmetric coordinate method to calculate the active power P and the reactive power Q from a phase voltage signal and an alternating current signal.

Active power adjusting unit 506B and reactive power adjusting unit 507B issue current commands ID * and IQ * so that an active power command P * and a reactive power command Q * correspond to the values calculated P and Q, respectively. The AC current setting unit 508B performs a control operation such that the command values obtained by bisecting the current command ID * correspond to the measured / calculated values ID1 and IQ1, respectively, and performs a control such that the command values obtained by bisecting the current command IQ * correspond to the measured / calculated values ID2 and IQ2, respectively. Outside of the DC setting units 1809A and 1809B, the DC setting unit 1809A performs a control operation such that the command values obtained by dividing a DC command ICC * which is obtained by dividing an output command value P * by an output voltage command VCC * from the DC power supply corresponds to the measured / calculated value ICC1 and the direct current setting unit 1809B performs a control operation such that the command values obtained by dividing the DC command ICC * which is obtained by dividing the output command value P * by the output voltage command VCC * from the DC power supply corresponds to the measured / calculated value ICC2.

In the present embodiment, the degree of freedom of a current path is six, where there are four integration calculators in the alternating current adjustment unit 508B and there are two integration calculators in the direct current adjustment unit. This means that there are six calculators in total. Therefore, all integration calculators can independently keep the input bias at zero. Each of the inverse d-q converters 1810C and 1810D performs a calculation according to Expression 3.

A DC voltage command correction computing unit 1811A is provided for arms 1504R1, 1504S1, and 1504T1, and the computing unit issues output voltage commands VR1 *, Vs 1 *, and VT1 *. A DC voltage command correction computing unit 1811B is provided for arms 1504R2, 1504S2, and 1504T2, and the computing unit issues output voltage commands VR2 *, VS2 *, and VT2 *.

Consequently, when the three-phase terminals (R1, S1, T1) and (R2, S2, T2) of the two sets of parallel windings of the 1502A AC rotating electrical machine have equal phase voltages of (VR *, VS * VT *), the output voltage commands VR1 * and VR2 * for arms 1504R1 and 1504R2 are given by

respectively.

The PWM calculation units 1812A and 1812B thus issue the gate commands Gate1 * and Gate2 * based on those output voltage commands and the capacitor voltage VC of the unit converters 103.

(Fifth mode of realization)

Figure 19 is a control block diagram of the control device 905 according to the fifth embodiment. Reference numbers identical to those assigned in Figure 13 indicate identical components, which will not be described to avoid repetition.

In the present embodiment, a reversible pump or pump turbine is directly connected to a synchronous machine 902A that includes a damper winding in accordance with a system of the present invention, where a sealing valve is provided on the side of pump discharge or reversible turbine pump. A rotational speed command generator 1901 receives a total pump head signal Hp and outputs a speed wp at which the input Pp at the time the water pressure is established corresponds to the motor input Pm at the time of acceleration determined by the characteristics of the variable speed motor-generator system. The rotational speed command generator can be simplified as a command generator that generates a fixed value when the fluctuation range of the total head of the pump is small. A rotation speed setting unit 1902 sets a current command ID * such that the variation between a rotation speed command wp * and a rotation speed frequency w is equal to zero. A command switch (SW5) 1903 changes the iD * of the current command based on the rotational speed command wp * and the rotational speed frequency w, which are criteria.

Figure 20 illustrates a starting procedure of the alternating current generator-motor system in the aforementioned embodiments illustrated in Figures 9 and 19. Reference numerals identical to those assigned in Figure 14 indicate identical components, which are not describe to avoid repetition.

When the MMC converter starts at time Tm2 (MMC control_ON), the AC rotating electric machine 902A is started in an induction machine mode by a snubber winding so that the active power Pm starts to increase from zero. The MMC converter stops temporarily (MMC control_OFF) when the rotational speed w reaches a value equivalent to a set value wS at time Tm3, at which time the active power Pm returns to zero. A CBE3 is closed to connect to field power converter 911. Then at time Tm4, a CBE2 opens to disconnect resistor 913. At the same time, a command switch SW1 is switched to the speed frequency side of rotation w while a command switch SW4 is switched to the output side (AVR) of the voltage adjusting unit 1308. This causes each of the ID * and IQ * commands to generate a command value proportional to speed. Field control starts at the same time (field control_ON). When the control of the MMC converter (MMC control_ON) is started at time Tm5 while maintaining the state mentioned above, the machine starts to accelerate with the synchronous torque of the machine. The voltage and current in this period are proportional to the rotational speed w, so that the motor input Pm increases in proportion to the square of the rotational speed w. On the other hand, the input Pp at the time the water pressure is set increases gradually according to the rotational speed w but to a lesser degree than the change in the motor input Pm; therefore there is certainly the rotational speed w at which the two correspond to each other. While this value varies according to the range of the total pump head or the specific turbomachinery rate, the value empirically falls between 50% and 90% when the rotational speed at nominal input equals 100%. Speed command generator 1901 calculates this value to be issued as the rotational speed command wp *. Once the rotation speed w is accelerated to the command value wp *, at time Tm8, the current command ID * output from the command switch SW5 is switched to the output (ASR) of the drive unit. rotation speed setting 1902 while at the same time the command switch SW4 is switched to the output side (AQR) of the reactive power setting unit 507A. The motor input Pm is temporarily reduced at time Tm8 to stop acceleration, but once the seal valve is opened to set the water pressure (seal valve_open) at time Tm9, the motor input Pm increases again in response to a sudden increase in the pump or pump turbine input Pp. To avoid fluctuation of the motor input Pm during this period, a time to open the sealing valve can be set so that the time difference ATp between time Tm9 and time Tm8 is as small as possible to increase the accuracy of the rotation speed command generator 1901 and reduce APp. When the fluctuation in the rotation speed in the water pressure setting is set by the rotation speed setting unit 1902, at the time Tm10, the command switch SW5 changes the current command ID * to the output. (APR) of the active power adjustment unit while the command switch SW3 is switched to the command P * side, so the machine enters into operation in a normal variable speed motor mode.

According to the present embodiment, a water level depression device is not required as the starting torque can be ensured, whereby the pump or pump turbine filled with water can accelerate from rest to be able to reduce start-up time. The acceleration time can also be shortened because the machine can operate with the upper limit of the output current capacity of the unit converters 103 during the acceleration period. In addition, the fluctuation of the motor input in setting the water pressure can be minimized; therefore no load adjustment is required or similar to the AC system required in a conventional pump; therefore, flexible operation can be implemented.

While the three-phase AC rotary electric machine has been described as an example in the above-mentioned embodiments, it goes without saying that the embodiments of the present invention can also be used for an N-phase AC rotary electric machine. Furthermore, although twist winding has been described as an example of the winding method in the above-mentioned embodiments, it goes without saying that each embodiment of the present invention can also be used for wave winding.

List of reference signs

101A, 901, 901A, 901B, 1501 DC power supply

102A, 102B, 902A, 1502A AC rotary electric machine

903 AC system

904, 906, 912, 914, 1506 switch

1001, 1002, 1601 transformer

1003 three terminal reactor

920 home power supply system

908 field winding

909 field breaker

910 field transformer

911 field power converter

913 resistance

917 current limiting resistor

915 initial load transformer

916 initial charge switch

918, 1518 initial load connection switch

919 Bypass Circuit Breaker

109A, 109B, 609, 905P, 905N, 907A, 907B, 1505, 1507 disconnector

104RP, 104SP, 104TP, 104RN, 104SN, 104TN, 604R, 604S, 604T, 1004UP, 1004VP, 1004WP, 1004UM, 1004VM, 1004WM, 1504R1, 1504S1, 1504T1, 1504R2, 1504S2, 1504T2, 1602W, 1602W arm

106 DC current transformer

107A, 107B, 107C, 107D, 208, 607, 507A, 507B DC voltage transformer

103 unit converter

201, 202, 212, 213, 214, 215 switching device

105A, 605A, 905, 1605 control device

203 capacitor

204A, 204B fiber optic cable

205A, 205B photoelectric conversion element

206A series-parallel conversion circuit

207A door controller

209 analog-digital converter

210 series-parallel converter

211 electro-optical conversion element

501A, 501B, 1801A phase voltage calculating unit

502 speed calculation unit

503A, 503B moving average calculation unit

504P, 504N, 504C, 1804A, 1804B d-q converter

505A, 505B, 1306, 1806 power calculation unit

506A, 506B active power adjustment unit

507A, 507B reactive power adjusting unit

508A, 508B AC drive unit

509A, 509B, 1809A, 1809B direct current setting unit

510P, 510N, 510C, 1810C, 1810D reverse d-q converter

511P, 511N, 511C, 1811A, 1811B DC voltage command correction calculation unit 512P, 512N, 512C, 1812A, 1812B PWM calculation unit

1301, 1304, 1305, 1310, 1903 command switch

1302, 1303, 1309 current command generator

1307 voltage command generator

1308 tension adjusting unit

1901 rotational speed command generator

1902 rotation speed adjusting unit

Claims (2)

1. A variable speed generator-motor system comprising a power converter connected to a DC power source (901), comprising a positive pole (P) and a negative pole (N), and a three-phase synchronous machine ( 102B) which has damping coils and connected to an AC side through three terminals (R, S, T), in which the three terminals (R, S, T) are connected to neutral points (Ux, Vx, Wx) of three sets of three-terminal reactors (1003) and are configured to connect to a three-phase transformer (1002), some first terminals (Up, Vp, Wp) of the three-terminal reactors (1003) are connected to terminals (a) on the side of the two-terminal three-arm machine (104RP, 104SP, 104TP) on the positive pole side of a modular multilevel converter, MMC, which are made up of k series connected two-terminal unit converters (103) that are configured to output an arbitrary voltage through an energy storage element (203) that has the characteristic of voltage source, where k is a natural number equal to one or greater, and terminals (b) of the positive pole of the arms are star connected to the positive pole (P) of the DC power supply (901), a few second terminals (Um, Vm, Wm) of the three-terminal reactors (1003) are connected to terminals (b) on the side of the two-terminal three-arm machine (104RN, 104SN, 104TN) on the negative pole side of the modular multilevel converter, MMC, which are made up of unit converters connected in series (103), and terminals (a) of the negative side of the pole of the arms are star connected to the negative pole (N) of the power supply of CC (901), the variable speed generator-motor system further includes: a first controller (905) configured to adjust a frequency and amplitude of current supplied from the power converter to the synchronous machine (102B) to a fixed value; a second controller (905) configured to synchronize a frequency of current supplied from the power converter to the synchronous machine (102B) with a rotation speed of the synchronous machine (102B) and to adjust an amplitude of the current to a proportional value to the frequency; the variable speed generator-motor system being configured to use the first controller (905) or the second controller (905); and a switch (912, 914) configured to short-circuit a field winding (908) of the synchronous machine (102B) with a resistor (913) when the first controller (905) is used and to connect the field winding (908) of the synchronous machine (102B) to an exciter (911) when the second controller (905) is used, and The variable speed generator-motor system is configured to use the first controller (905) when the synchronous machine (102B) starts from rest, and to switch the control to be performed by the second controller (905) once the frequency reaches a set value, and wherein the variable speed generator-motor system is further configured to temporarily stop the MMC power converter when the frequency reaches the set value, to allow connection of the exciter (911) through the switch (912, 914). 2. The engine-variable speed generator according to claim 1, in which system A reversible pump or pump turbine is provided with a sealing valve on one discharge side and is directly connected to the synchronous machine (102A, 102B) having damping windings, the variable speed generator-motor system includes a third controller (905) configured to generate a rotational speed command in response to a signal from the pump head or reversible pump turbine and to adjust the rotational speed to the rotational speed command, the second controller (905 ) configured to detect the acceleration for the rotational speed command, and the variable speed generator-motor system is further configured to open the sealing valve when the second controller (905) detects the acceleration for the rotational speed command, and then to change the control to be performed by the third controller (905).